The present invention relates to a control method of a thermostatic system and, more particularly, to a control method applicable to a water heater, wherein two electromagnetic valves are exploited to exactly control gas outflow at the gas outlet. Thereby, thermostatic control of the water heater can be achieved.
As shown in FIG. 1, a gas switch control system 10 is installed in a prior art water heater. The gas switch control system 10 comprises a gas inlet 11 for inputting gas, a first gas outlet 12 for outputting gas to a main stove, and a second gas outlet 13 for outputting gas to a pilot flame. A valve 14 is arranged between the gas inlet 11 and the first gas outlet 12 and the second gas outlet 13. The action of the valve 14 is controlled by a water pan 15. When cold water is input from a cold water inlet 16 into the water pan 15, the valve 14 will be pushed open so that gas can be transferred from the gas inlet 11 to the first gas outlet 12 and the second gas outlet 13.
A switch middle seat 17 is installed between the first gas outlet 12 and the second gas outlet 13. The switch middle seat 17 comprises an upper lid 18 and a bottom seat 19, which are assembled to form a hollow shell. A valve sheet 20 made of resilient material such as rubber is installed in the switch middle seat 17. The valve sheet 20 is fixedly gripped between the upper lid 18 and the bottom seat 19. The valve sheet 20 is connected to a connecting link 21. One end of the connecting link 21 has a valve 22. The valve 22 can be used to control the open or close of the first gas outlet 12.
The valve sheet 20 partitions the switch middle seat 17 into a first gas room 23 and a second gas room 24. A first electromagnetic valve 25 and a second electromagnetic valve 26 are installed on the side wall of the second gas room 24. The first electromagnetic valve 25 is normally open and situated between the first gas room 23 and the second gas room 24. The first electromagnetic valve 25 can be used to control the open or close state between the first gas room 23 and the second gas room 24. The second electromagnetic valve 26 is normally close and situated between the second gas room 24 and the second gas outlet 13. The second electromagnetic valve 26 can be used to control the open or close state between the second gas room 24 and the second gas outlet 13, i.e., the open or close of the second gas outlet 13.
When cold water is input from the cold water inlet 16 into the water pan 15, the valve 14 will be pushed open through the water pan 15. Therefore, gas can be transferred from the gas inlet 11 into the first gas room 23 of the switch middle seat 17. Gas can also be transferred via the first electromagnetic valve 25 at open state to the second gas room 24. At this time, the second electromagnetic valve 26 can be controlled to be open so that gas can be transferred to the pilot flame via the second gas outlet 13, hence facilitating action of ignition. When the pilot flame has been ignited, the first electromagnetic valve 25 can be controlled to be close so that gas in the second gas room 24 will be gradually burned out. At this time, the gas pressure in the first gas room 23 will be larger than that in the second gas room 24. Therefore, gas will push the valve sheet 20 to move toward the direction of the second gas room 24. The valve 22 will be jointly moved toward the direction of the switch middle base 17 through the connecting link 21. The first gas outlet 12 can thus be controlled to be open so that gas can be output via the first gas outlet 12 to the main stove.
However, in the above gas switch control system 10 of prior art, the first electromagnetic valve 25 and the second electromagnetic valve 26 can only make a simple on or off action. Gas outflow of the first gas outlet 12 output to the main stove can not be exactly controlled so that thermostatic control of the water heater can not be achieved.
The primary object of the present invention is to provide a control method of a thermostatic system, wherein two electromagnetic valves of a thermostatic system of a water heater can be controlled to perform the control of gas charge and discharge of a second gas room so as to push a valve sheet forwards or backwards. Thereby, gas outflow of a first gas outlet output to a hot water heater can be exactly controlled so that the linkage with temperature change of the water heater is more apparent. Thermostatic control of the water heater can thus be achieved.
To achieve the above object, the present invention provides a control method of a thermostatic system. When gas outflow output to a main stove is too large, the first electromagnetic valve is controlled to be open and the second electromagnetic valve is controlled to be closed. Gas will be transferred from the first gas room to the second gas room. The control of gas charge of the second gas room is thus performed so as to decrease the open degree of the first gas outlet used to output gas to the hot water heater, hence decreasing gas outflow. When gas outflow output to the hot water heater is too small, the first electromagnetic valve is controlled to be closed and the second electromagnetic valve is controlled to be open. Gas cannot be transferred to the second gas room, and gas in the second gas room can be output via the second gas outlet used to output gas to a pilot flame. The control of gas discharge of the second gas room is thus performed so as to increase the open degree of the first gas outlet, hence increasing gas outflow.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings, in which: